Pneumatic counterbalance for flying hot saws



Nov. 18, 1952 V w. RODDER 2,618,045

PNEUMATIC COUNTERBALANCE FOR FLYING HOT SAWS Filed Nov. 29, 1949 s Sheets-Sheet 1 INVENTOR. WILL IAM PODDf/P ATTORNEYS Nov. 18, 1952 w. RODDER 2,613,045

PNEUMATIC COUNTERBALANCE FOR FLYING HOT SAWS Filed Nov. 29, 1949 5 Sheets-Sheet 2 IN V EN TOR. W/LL lAM EODDER A 7' TOENEYS Nov. 18, 1952 w. RODDER PNEUMATIC COUNTERBALANCE FOR FLYING HOT sAws Filed Nov. 29, 1949 5 Sheets-Sheet 3 m kmw INVENTOR WILL IAN EODDER ga fl A TTOiP/VEYS Nov. 18, 1952 w. RQDDER PNEUMATIC. COUNTERBALANCE FOR FLYING HOT SAWS Filed Nov. 29, 1949 5 Sheets-Sheet 4 INVENTOR. WILL lAM PODDEE A TTOP/VEYS Nov. 18, 1952 w. RQDDER PNEUMATIC COUNTERBALANCE FOR FLYING HOT SAWS s sheets-sheets Filed Nov. 29, 1949 A l R UNDER PRES SURE INVEN TOR. WILL lA/V EODDER A TTOR/VEYS Patented Nov. 18, 1952 TENI ICE PNEUMATIC COUNTERBALANCE FOR r2531?xaFLYINGgI-IOT SAWS g 1 William Rodderiioungstown, Ohio, assignor to jThe-,zAetnagastandard Engineering Company,

Youngstown, Ohio, a corporation of Ohio I Application Ndveihb'r 29, 1949, Serial No. 130,055

This invention relates to a balancing system for a imetal working machine incorporatinga cutting tool'moving in an orbital path, as, for ex-.

ample,- a= flying hot saw-of the-kind shown, .dee scribed, and claimed inspriorapplication :Serial No. 69,521, filed-January 6,1949, in the name of Wi1liam Rodder, a

fixed size shape andlocatiom- Fonpredetermined.

set-tings'of the crank armsusually about midway of' their lengths; the moments of the counter-.

weightsrapproximately equal the moments of the crank assemb1ies,-. but for: all other: settings there will of necessity r-be-some degree .of unbalance in the-system. in generak-the; greater the degree of-adjustmentgeizeathe greater-the departure from the -setting at which the moments of the counterweightsmqual the moments of the crank assemblies; the; greater;-the-degree -of unbalance;

It is: an :object ofathe present inventionto improvetupon this state pf afi' airs by incorporating inthe apparatus a (flexible balancing systemthat will comp1ement=the counterweights inthe event that unbalance is developed, as, forexample, by adjustment of the lengthsof thecrank =arms. Such :balanci-ng system; can take, any of various forms. It may employ arpressure fluid which may be eithena; gasaorha-liqui d; shut-preferably the former. ;;.In- -apreferredembodiment of the in,- 'vention, the balancing system), includes one or more fluid-pressure motors which assist in;- over; coming the. unbalance The use in {the apparatusapf ;Lsuch a .balancing system achieves a principal object ofwthe rinventiongwto (wit, automatic compensationt iorunbalance without necessitatingithe umaliin'gtof extensive external or internalnadjustments, ;as, for example, by replacingfmerkelocating counterweights.

Other objectsand advantages of the invention will be apparent v.Ironzr the. accompanying 'draW- I ings, .in whichFigure 1' is agsidevelevation of a flying-hot saw embodying theebaiancing'system of .the present invention; Figure; 2a is a corre spondinglplan; Figure 3-is a vertical section-with partsin elevation, taken. immediately to the rear -ri urivee' ar iethe yi s tsaw ofri ures L '18" claims: (01. 29- 69?- 1 and 2; Figure 4 is a detail of the nature or a section taken on line 44 of Figure 3; Figurej is a section taken in part. on line 5-15 of Figure 3 and in part on a'plane passing through the axes of hollow shafts 26 and 21, forconvenience of illustration; Figure 6 is an enlarged elevation, somewhat simplified, of the balancing systemin: corporated the flying hotsaw of Figures 1 and 2; and Figure 7 is a detail of the nature of an elevation, of;,part of. the piping system as seen fromiine .1-.l of Figure 6 For CORK/611:.

ience, theflying hot saw shown in the drawings asembodying the invention is inthe main, but

not in all details, the fiying hotsaw shown in the drawings of theabove-identified prior. ap plicationsi I L As illustrated in Figures 1 and 2 of the drawings, the, flyinghot saw in which the invention isshown as; incorporated comprises a base sec-,

tion, indicatedin general at [0, that is supported on the mill floor, and a top section, indicated in general atv II, mounted upon the base section. The two sections. are adjustably mounted with respectto each other in a. manner permitting top section H, to be moved up orldown onubase sec-. tion,lii. ,The topsection carriesa circular saw, together with mechanism for moving the saw in anorbital path. The base section is pro vided with suitable. guidesfor-the ork W, which mayftake the-form ot pipe. It. carriesa workdeflecting cam,,together with the mechanism for, operating ,it.-- The cam 14p is pear-shaped, notchedg and mounted for rotationon a shaft carried, byan eccentric By properrtiming of the eccentric, cam I4 is caused to deflect the work periodicallyinto the path of circular saw|6.;- 1-H fr;

Saw I6 is driven by an electric motor, being mounted :directly on the motor shaft,- and is par; ti-ally encloseduwithin -a guard 2|; The motor, saw andiguard are supportedby a suitable frame member 22. 'I'h saw assembly so made up 'is carried. inwa circular orbit by a two substantially identical adjustable cranks 24 ,and ;2;5-, which cranks mount the assembly in, such mannerpthat theaxis of, the motortand saw extends parallel and the plane of the sawblade extends perpen dicularly to the path of Work W. flfhecran ks 2 4 and 25 are supported on the projecting end por tions of hollow shafts-wand '21,: shown in Figure -5, suchf shafts being driven through inter n ne r w r tra sairpmfi m nyd i WW 2 n1ount ed. on-top section ti attherear of the apparatuses a whole Motor 2 9' operates at a speed proportionaluto the spee Of the mill delivering work W to the apparatus, conventional electrical controls indicated diagrammatically at 28 bein provided for this purpose.

Hollow shafts 26 and 21 are rotated in synchronism with each other and in the same direction, usually counterclockwise as seen from the front of the apparatus as a whole, by means of gears 59 and The gears are themselves driven by a pinion 52 carried by main drive shaft 53. The latter is driven by main drive motor 29 through a speed reducer 33, a P. I. V. (positive infinitely variable) drive 3!, and coupling 54 (Figures 1, 2 and 5). The relationship between the rotational speed of main drive motor 29 and the speed of the work W passing through the apparatus is fixed and maintained by means of the controls 28 for motor 29. By this arrangement, it becomes possible to adjust the rotational speed of the saw assembly, and therefore the length of the sections into which work W is being out, by adjusting P. I. V. drive 3!. Adjustment of P. I. V. drive 31 is eifected by means of the adjusting motor 35 appearing in Figure 2 to the rear of upper member 55a of two-part gear housing 55a, 5512.

In order to maintain the lineal speed of the saw assembly at the time the cutting action takes place as close as possible to the lineal speed of work W, it is necessary to change the radius of the cranks whenever the length of the sections being out is changed. As has been indicated, the latter is done by increasing or decreasing the rotational speed of the saw assembly. When the rotational speed of the saw assembly is increased, the length of the cranks must be decreased sufficiently to maintain substantially constant the lineal speed of the saw assembly in its orbit. The reverse action is required when the rotational speed of th saw assembly is decreased. These adjustments in the length of the cranks may be effected by means of adjusting motor 36 through mechanism appearing toward the upper left-hand corner of Figure 5 but more fully disclosed in the prior application, to which reference may be had for detailed information as to the precise mode of adjustment.

Whenever the length of the cranks is to be increased or decreased, the position of top section II with respect to base section must be appropriately adjusted in order to maintain the lower edge of circular saw I6 in proper relation to the path of Work W. To this end, top section If is supported on base section l9 by screw jacks (not shown) disposed at th four corners of base section IQ. These screw jacks can be adjusted by adjusting motor 36 with or without change in rotational speed or change of length of cranks 24 and 25. Thus with the cranks set for an intermediate radius of, for example, 22 inches, top section II of the machine, and, correspondingly, the center line of the cranks, can be raised or lowered by adjusting motor 36 in order that the lowermost point in the travel of the saw may be at substantially the same level at all times. By these adjustments, the speed of rotation of the saw assembly, the position of top section II relative to base section [0, and the length of cranks Z4 and 25 can be changed simultaneously.

Inasmuch as the saw assembly and cranks 2d and 25 are necessarily massive, it is desirable to counterbalance these parts. To this end, counterweights 96 and 91 are secured to hollow shafts 26 and 2?, preferably as close as ossib bearings 98 and 99. The counterweights may be simple steel castings of appropriat size, weight and location; however, the largest portions of the counterweights necessarily project oppositely tocranks 24 and 25. schematically the outlines of such counterweights. The hub portions of the counterweights appear in section in Figure 5, the parts indicated in dotted lines being disposed above the section.

Such counterweights cannot be readily changed; consequently, when cranks 24 and 25 are lengthened to something more or shortened to something less than an assumed neutral medial radius of 22 /2 inches, a condition of unbalance results. If, for xample, the cranks are lengthened to a typical maximum of 2'7 inches, having been counterbalanced for a length of 22 inches, unbalance results due to the fact that the moments of the cranks and associated mechanism exceed the moments of the counterweights and, in effect, th counterweights become too light. Similarly, if the cranks are shortened to a typical minimum of 18 inches, having been counterbalanced for a length of 22 inches, unbalance results due to the fact that the moments of the counterweights exceed the moments of the cranks and, in ffect, the counterweights become too heavy. In typical situations such unbalance may result in nonuniform rotational speed of the assembly and vibration of the apparatus with reduction in the accuracy of the lengths cut by the saw.

To compensate for unbalance so introduced, the balancing system of the present invention is arranged to apply forces to rotating parts of the apparatus which can be controlled by the operator in accordance with what is required to act either in the same direction as or in the opposite direction to the action of the force of gravity on the cranks and associated mechanism. In general, as will appear, a preferred form of such balancing system is made up of two like crank means in the form of eccentrics, two rocker arms, and two fluid-pressure motors. The latter overlie the nds of the rocker arms. The rocker arms overlies the eccentrics. The eccentrics are mounted on hollow shafts 26 and 2! in the space immediately to the rear of gears 50, El and pinion 52. Thus the introduction of the balancing system into the apparatus requires no important rearrangement of parts but mainly the addition of certain elements hereinafter described.

As indicated in Figure 3, the balancing system of the present invention includes th two eccentrics Illl and I02, respectively mounted on hollow shafts 26 and 21, which eccentrics are of similar construction and, in general, similarly related to the apparatus as a whole. Eccentrics [ill and I02 embody sleeve portions I83 and we fixed by keys I05 and )6 to hollow shafts 26 and 21, respectively. Midway of each such sleeve, a web projects radially, such webs being designated l0! and H18. The webs terminate in circular collars I09 and H0, respectively, such collars being eccentric to the axes of hollow shafts 26 and 21. Collars H39 and H0 are short in length compared to bushings I03 and H14 but each is characterized by the presence on its outer face of a flange which cooperates with the remainder of the structure in the manner hereinafter described. One such flange, the same forming part of collar I09, appears in section in Figure .5 of the drawings. Because of Figures 1, 2 and 5 illustrate 5.. the presence of thewebs; eccentrics IOI andv I02 have crescent-shaped recesses on opposite sides thereof, recesses IIIa andv II I b shown in Figure flanking web I01 and two like recesses (of which only one, II2a, appears in the drawings) flanking web I08.

Surrounding collars I 99 and IIO and fitting snugly around the above-described flanges forming part of the collars are bronze. bearings I I4 and H5, both of which appear in Figure 3 and one of which, II 4, appears in transverse cross-section in Figure 5. Bearings H4 and H5, which are characterized by H-shaped sections,

receive the flanges on collars I09 and H0 on one side thereof and on the other are surrounded by eccentric straps which are generally circular in shape and ar made up of connectors H6 and II! and clamps H8 and H9 fixed to the connectors by bolts or the like. Pins I and I2l locate bearings H4 and H5 relative to connectors II 6 and Ill, thus precluding rotation of such bearings within the connectors. Collars I09 and III) rotate in the bearings i-n response torotation of hollow shafts 26 and 21. As shown in Figure 3, at the two sides of pins I20 and I 2| are lubrication openings I22a, I 22b and I23a, I 23b, one of which, opening I23a, appears in plan in Figure 5.

Connectors H6 and Ill are provided with necks I 29 and I25 within'which are circular Openings in which are received connector pins I26 and I27, respectively. The latter are supported in and by the two rocker arms designated 528, and I29, the former of which cooperates with eccentric IllI and the latter of which cooperates with eccentric I02. Rocker arms I 29 and I29 are of Welded construction, being built up of sheet or plate material. Rocker arm I23 includes far side piece I304; while rocker arm E29 includes far side piece I3Ia, both of which side. pieces appear in elevation in Figure 3. In each case, a near side piece parallels the side piece shown in Figure 3, such near or second side piece in the case of rocker arm I29 being shown in section in Figure 5, wherein it is designated I 3Ib. At their left-hand ends, theside pieces making up rocker arms I28 and I29 are separated by spacers I32 and I33, respectively, such spacers taking the form of bronze-lined sleeves that are rigidly affixed at their opposite ends to the two side pieces.

Pin I94 at the left-hand end of rocker arm I28.

is carried by supports of the nature of ears attached to upper housing member 55a, one of which, I36, appears in elevation in Figure 3. A similar support I91, likewise taking the form of an ear, is represented as carrying pin I 35 at the left-hand end'of rocker arm I29. Rocker arms I28 and I29 pivot about pins I34 andl35, respectively. Extending generally lengthwise of rocker arms I 28 and I 29, respectively, are the relatively long reinforcing plates I39 and I49 and the relatively short reinforcing plates I4I and I42, all of which appear insection in Figure 3. Reinforcing plate I42 also appears in elevation in Figure 5. Reinforcing plates I39 and I M on one hand and I49 and I92 0n the other are separated by a space sufficient to accommodate necks I24 and I25 of eccentrics. IOI and H32.

At their right-hand ends, rocker arms I29 and I29 are provided with yokes formed of opposed yoke arms, one on each side piece. Far yoke arm I93a at the right-hand end of rocker arm I29 and far yoke arm I490; at the right-hand end of rocker arm I29 both appear in Figure 3 while 7 6, both far yoke arm MM and near yoke arm I44b. appear in section in Figure 5. Extending in each case from one to the other of the two opposed yoke arms and projecting through openings therein are wrist pins- I45 and I 46, the former at the free end of rocker arm I28 and the latter at the free end of rocker arm I29; Wrist pins I45 and I49 are respectively surrounded by and carried in bronze-lined bearing sleeves ll'and I48 at the lower ends of piston rods I49 and I50. Thus angular movement of rocker-arms I28 and I29 in response torotary movement of eccentrics WI and I02 is communicated to piston rods I49 and I50, wherein it manifests itself as linear movement; similarly, linear movement of piston rods I49 and I50 imposes angular movement on rocker arms I28 and I29 and rotary movement on eccentrics IOI- and I02.

The eccentrics, which are, of course, equivalent to cranks are secured to shafts 2fi-and 21 in such positions that their equivalent cranks project from the'shafts 26 and 2'! in the same directions as the cranks 29 and 25; i. e., in the position shown in Figure 5, the cranks 24 and 25, which are not visible in this figure, extend horizontally to the left of shafts 26 and 21 and the equivalent cranks of eccentrics I9! and I02 extend in the same direction. Thus forces exerted downwardly on the eccentrics act in the same direction as gravity'acts on the cranks 24 and 25 and associated assembly, while forces acting upwardly on the eccentrics act in the same direction as gravity on the counterweights 96 and 91. Thus if the cranks are shortened beyond their assumed middle length of 22% inches, they will be in effect too light and the counterweights too heavy; this unbalance can be compensated by exerting downward forces on the eccentrics through piston rods I99 and I50, whereasunbalance caused by an increase in length of the cranks beyond their assumed middle length can be compensated for by applying upward forces on the eccentrics "through the piston rods.

In order to make possible the application of tively include top cylinderheads I55 and I56, I

bottom cylinder heads I51 and I58, and packing glands I59 and IE0. As shown in Figures 3 and 4, cylinders I53 and I54 have at their bases and on their near sides as seen in Figure 3 integrally formed bosses I 6| and I 62 through suitable openings in which pressure fluid can be admitted or exhausted. Overlying .bosses I6! and I62 are two like bosses I63 and I 64, the same being located near the tops of cylinders I53 and I54 and on the near side. of the cylinders as seen in Figure 3. Like bosses I6I and IE2, bosses I 63 and IE4 have openings drilled therein to permit pressure fluid to pass therethrough. By means. of

connecting pipes I65 and I95, such pressure fluid may pass therebetween as indicated in Figure 4, being admitted to or exhausted from the space above the piston. On the far side of cylinders I53 and I54 as seen in Figure 3 and at the base 7. Like the bosses previously described, the bosses on the far side of cylinders I53 and I58 are drilled to permit pressure fluid to be admitted Or exhausted therethrough, the openings therein communicating with the spaces below the respective cylinders.

Surrounding the bosses at the lower ends of the cylinders are suitable mounting sleeves, two of which, I68 and I69, appear in section in Figure 4. Such sleeves, which are drilled and tapped to receive lines carrying pressure fluid to and from the cylinders, are for the purpose of locating the bosses in proper position within the cylinder housings. The latter, designated I18 and HI, surround cylinders I53 and I54, respectively, as shown in Figure 3. They are surmounted by double outlet vents I12 and I13. Cylinder housings I19 and HI are respectively supported on cylindrical foundation pieces I14 and I15 which are connected by a triangular superstructure I16 made up of two like halves "Ta and H112. A triangular end flange, designated I18, is mounted after the fashion of a buttress as indicated in Figures 2 and 3, thus lending additional strength and rigidity to foundation pieces I14 and I15 and superstructure I16.

By means of the piping system shown in Fig ures 1, 2, 6 and '7, the pressure fluid, ordinarily air, is admitted to and exhausted from the spaces in cylinders I53 and I54 above and below pistons I 5| and I52. A conduit I80, which branches as shown in Figure 2 into two lines I82 and I 83, supplies air to or withdraws air from the space above the pistons, communicating therewith in the manner indicated in Figure 4. A conduit I8I, which branches into two lines I84 and I85, supplies air to or withdraws air from the spaces below the pistons, communication with the spaces below the pistons being as indicated in Figure 4 through the bosses at the rear of the cylinders. Conduits I86 and I8I are seperately connected at their lower ends to a hand-controlled four-way illgllve I86 equipped with and operated by a handle By moving handle I81 from one to the other of the two extreme positions I 81a and I81?) indicated in Figure 1, it is possible to reverse the direction of flow of air to and from cylinders I53 and I54. With handle I 81 in position I81a, air under pressure is admitted through conduit I89 and lines I82 and I83 to the spaces above the pistons and discharged by means of lines I84 and I85 and conduit I8I from the spaces below the pistons, thereby tending to force the pistons downward. If, however, handle I81 is moved to position in I81b, air under pressure is admitted through conduit I8I and lines I84 and I85 to the spaces below pistons I5I and I52 and the air in the spaces above the pistons is exhausted through lines I82 and I83 and conduit I88, thereby tending to force the pistons upward. Thus air under superatmospheric pressures ranging upward to perhaps 100 pounds per square inch but in a typical case at a pressure of perhaps 4'5 pounds per square inch can be admitted simultaneously above the two pistons to bias them downward or below the two pistons to bias them upward while the opposite ends are at substantially atmospheric pressure.

Control valve I86 communicates by means of a conduit I88 (see Figure 2) with a pressure tank I89 provided on the far side thereof with a relief valve I90 and on the near side with a drain valve I9I. Tank I89 is supplied with air at a constant pressure by means of a line I92 in which is in- 8 corporated an adjustable pressure regulating valve I93. Air being exhausted from the cylinders passes from valve I86 through a conduit I95 into an exhaust tank I96. As indicated in Figure 6, tank I96 is provided with a breather device I91 and a drain valve I98; air conveyed to tank I96 through conduit I95 is exhausted to the atmosphere through breather device I91. With this arrangement the force exerted by the piston for any given setting of the valve I93 is substantially constant at all times. Tanks I89 and I96 are mounted as shown in Figures 1, 2 and 6 toward the rear of top section II just forward of main drive motor 29.

In the operation of the balancing system, if crank arms 24 and 25 carrying the saw assembly are being shortened to something less than their assumed middle length of 22 /2 inches, valve I86 is moved manually into position I81a. In consequence, air under pressure is supplied to the spaces above the pistons, air for that purpose passing from pressure tank I89 through conduit I88 to control valve I86 and thence through conduit I and lines I82 and I83 to cylinders I53 and I54. At the same time, air from the spaces below the pistons is exhausted through lines I and I88 and conduit I8I. Because the crank arms are to be relatively short, the unbalance that will tend to result from the change in their length will be attributable to the greater moments of the counterweights; in effect, the counterweights will be too heavy and the crank assemblies too light; accordingly, it is necessary to brake the counterweights as they move down and the cranks move up. To that end, pistons I5I and I52 are urged downwardly by the pressure above them to urge the rocker arms downwardly, thus, in effect, adding to the weight of the crank assemblies.

On the other hand, if the crank arms are extended beyond their assumed middle length of 22 /2 inches, the unbalance will be attributable to the crank assemblies being in effect too heavy for the counterweights. Since the counterweights and crank assemblies are off-set from each other by air under pressure must be introduced into the spaces below the pistons by means of conduit I8I and lines I84 and I85 and exhausted from the spaces above the pistons by lines I82 and I83 and conduit I80. By moving control valve I81 into position I81b, the net effect will be to apply forces acting with the force of gravity on the counterweights; i. e., to urge the rocker arms upwardly and, in efifect, increasing the weight of the counterweights.

In either case, the accuracy of the balancing can be checked by an ammeter which measures the power supplied to the main drive motor 29. Variations in the reading of the ammeter during each revolution of the cranks 24 and 25 and associated assembly indicate that the balancing is imperfect and that adjustment should be made by means of pressure regulating valve I98 in the pressure of the air above or below the pistons, as the case may be. With proper adjustment, the rotating parts are efiectively balanced and variations in the angular Velocity of the cranks and of the saw assembly in its orbit due to unbalance are substantially prevented. Thus the accuracy of the lengths of pipe cut by the saw is improved.

From what has already been said, it is apparent that the balancing system of the invention need not necessarily take the precise form shown and described but may be varied in a great many and located in the apparatus, including'positioning them below the level of hollow shafts 2t and 21 rather than above them in the manner indicated in Figures 3 and 4. Numerous other changes may be made without departing from the spirit of the invention.

It is intended that the patent shall cover, by summarization in the appended claims, whatever features of patentable novelty reside in the invention.

What is claimed is:

l. A metal-working machine comprising a cutting tool; means for moving the tool in an orbital path, said means including a crank; a crank shaft on which said crank is mounted; a counterweight on said crankshaft; a power train; a motor driving the power train; and, located between the motor and the means for moving the tool, a pneumatic system acting to apply complementary balancing forces to said crank shaft, said pneumatic system including a fluid pressure motor.

2. A metal-working machine comprising a cutting tool; means for moving the tool in an orbital path, said means including a crank; a crank shaft on which said crank is mounted; a counterweight on said crankshaft; a power train; a motor driving the power train; and means acting to apply complementary balancing forces to said crank shaft, said means comprising a fluid pressure motor and a rocker arm coupled to said crankshaft to which the fluid pressure motor is linked.

3. A metal-working machine comprising a cutting tool; means for moving the tool in an orbital path, said means including a crank; a crank shaft on which said crank is mounted; a counterweight on said crankshaft; a power train; a motor driving the power train; and means acting to apply complementary balancing forces to said crank shaft, said means comprising a fluid pressure motor, a pivotally mounted lever arm to which the fluid pressure motor is linked, and an eccentric coupled to the 1ever arm but turning with said crankshaft.

4. A metal-working machine comprising a cutting tool; means for moving the tool in an orbital path, said means including a crank; a crankshaft on which said crank is mounted; a counterweight for the crank, said counterweight being coupled to said crankshaft; and a balancing system including a fluid pressure motor for applying complementary balancing forces to said crank shaft.

5. A metal-working machine as in claim 4 in which the fluid pressure motor is biased to oppose rotation of said crankshaft throughout substantially 180 of each revolution thereof and to assist rotation of said crank shaft throughout the remaining 180 of each revolution thereof.

6. A metal-working machine as in claim 4 in which the fluid pressure motor is coupled to an eccentric mounted on the crank shaft.

7. A metal-working machine as in claim 4 in which the fluid pressure motor is coupled by a pivotally mounted lever arm to an eccentric mounted on the crankshaft.

8. A metal-working machine comprising a cutting tool; a crank for moving the tool in an orbital path, said crank being adjustable as to length; power means for operating the crank; balancing means acting on the power means; and complementary balancing means imposing on the power means selectively variable compensatory forces negativing the efiects of unbalance resulting from a change in the length of the crank, said complementary balancing means being adapted to absorb power during a portion of each revolution of the crank and to supply power during another portion of each revolution thereof.

9. A metal-working machine as in claim 8 in which the complementary balancing means includes a fluid pressure motor comprising a cooperating cylinder and piston and means for supplying fluid under pressure thereto.

10. A flying hot saw comprising a prime mover; a power train driven by the prime mover; a counterweight incorporated in the power train; a fluid pressure system compensating for unbalance in the power train; a crank driven by the power train; a circular saw moved in an orbital path by the crank; and, cooperating with the saw, means for moving the work into the path of the saw.

11. A flying hot saw comprising a prime mover; a power train driven by the prime mover; a counterweight incorporated in the power train; a fluid pressure system compensating for unbalance in the power train; a crank driven by the power train, said crank being adjustable as to length; a circular saw moved in an orbital path by the crank; and, cooperating with the saw, means for moving the work into the path of the saw.

12. A flying hot saw comprising a prime mover; a power train driven by the prime mover; a counterweight incorporated in the power train; a fluid pressure system compensating for unbalance in the power train; a crank driven by the power train, said crank being adjustable as to length; a circular saw moved in an orbital path by the crank; and, cooperating with the saw, a cam for periodically deflecting the work into the path of the saw.

13. A metal-working machine comprising a cutting tool; a crank for moving the tool in an orbital path, said crank being adjustable as to length; power means for operating the crank; a counterweight for the crank, said counterweight being incorporated in the power means; and, imposing a compensatory load negativing the effects of unbalance resulting from a change in the length of the crank, a fluid pressure system acting on the power means.

14. A metal-working machine comprising a cutting tool; a crank for moving the tool in an orbital path, said crank being adjustable as to length; a crank shaft; a counterweight for the crank mounted on said crank shaft; a prime mover for operating the crankshaft; and, imposing a compensatory load negativing the effects of unbalance resulting from a change in the length of the crank, a separate power system acting on the crank shaft, said system being adapted to absorb power from said crank shaft during a portion of each revolution thereof and to supply power to said crank shaft during another portion of each revolution thereof.

15. A metal working machine according to claim 14 wherein the power system comprises a fluid pressure cylinder, a cooperating piston and means connecting them to the crank shaft.

16. A metal working machine according to claim 15 wherein valveimeans are proyided to supply fluid under pressure to either side or said piston whereby the direction of theforce exerted by said piston can be reversed.

17. A metal working machine according to claim 16 wherein fluid under pressure is supplied 'to said piston and cylinder from a pressure reservoir provided with pressure regulating means for controlling the pressure in said reservoir.

18. A flying hot saw. for severing successivev longitudinal sections from work such as pipe, tube, rod and the like, comprising a circular saw, a rotary support for carrying said saw a ci rcular orbital path, a shaft for driving said support, means for varying the radius of said rotary support, a fixed counterbalance on said shaft adapted substantially to'balance said rotary support and saw in one position of adjustment of said rotary support and means for compensating for unbalance'of said rotary support and saw resulting from adjustments in the radius of said rotary support, said compensating means com} prising a cylinder, a piston therein, means connecting said piston to said shaft, and means for supplying fluid under greater pressure to' one side of said piston than to the other side of said piston, whereby said piston acts to impose forces on said shaft tending tov assist rotation thereof throughout, substantially 1809- of each; revolutionthereof andto oppose rotation thereof throughout the remaining 180 of each. revolution thereof.

' WILLIAM RQDDER.

REF E ES ITE The following references are of record in the file ofthis patent:

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